The present invention relates to the art of cutting dies and, in particular, to an improved combination cutter assembly and method useful for cutting a stack of stock material.
It is known in the art of high speed manufacturing of stock material to employ a die cutter to stamp or punch shapes, especially irregular shapes, in stacks of layered stock material such as paperboard and cardboard for cartons and rigid or semi-rigid structures. Certain problems are encountered in high speed systems, however, relating directly to the cutting element alone, which is usually a steel rule cutting die, or in combination with the cutting surface such as a soft urethane material fixed to a steel back up plate.
For instance, a cutting die such as a steel rule die must be maintained in careful alignment so that the cutting edge is more or less perfectly parallel to the cutting surface to insure a complete cut through all layers of the stock material over the entire length of the cutting edge. Furthermore, since steel rule cutting dies can be expected to have a width of about 1/16" the cut is relatively thick and the cutting surface quickly becomes worn. Consequently, the cutting surface is often mounted on a wheel which revolves after one or several cuts, depending on the toughness of the cutting surface, to change the location of the striking cutting blade so that the surface and the back up material does not wear out.
The problems listed above are exacerbated and other problems are encountered when the stock material is extremely thin and deformable such as in the case of plastic sheet material. For example, when a stack of thin stock material having resiliency is subjected to the cutting pressure of a thick cutting blade the individual layers of material can easily be fused together thus inhibiting the ability to separate the layers. Furthermore, thin deformable layers at the bottom of the cutting stroke readily wrap, and stretch in the case of plastic sheet material, around the end of the cutting blade rather separate as a severence.
It is, therefore, an object of the present invention to provide an improved combination cutting assembly for stamping or punching a die cut in a layered stack of stock material.
It is a further object to provide a cutting assembly capable of efficiently and cleanly cutting a layered stack of thin, deformable and resilient stock material such as plastic sheet material.
It is yet a further object of the present invention to provide a die cutting means for high speed production of stock material which does not incur repeated problems such as hang up and fused sheet material.
Other objects and advantages over the state of the art are provided by the present invention as it is disclosed herein, which will become apparent to those skilled in the art, forth herein.